Process of producing catalyzing pictures.



no. 'zsasao.

ETATES Patented April 4:, 15305.

CATi LYZl N G SPEGIFI"ATION forming part of Letters Patent No. 786,640, dated. April 4, 1965.

Application illed November 6,1903. Serial No. 180,140.

To (I/Z7 1/ 71/0717/ it may concern:

Be it known that we, Osoan Gnos, doctor of philosophy and chemist, a subject of the German Emperor, and Janos Fninnm nnnnadoo tor of philosophy and chemist, a subject of the Emperor of Russia. both residents of Leipsic, in the Kingdom of Saxony, German Empire, have invented new and useful Improvements in Processes of Producing Catalyzing Pictures, of which the following is a full, clear, and exact specification.

in Letters Patent No. 770,533, dated September 20, 190i, is described aprocess for producingpictures from a silver negative by taking advantage of the catalyzing action of silver. It has now been found that when silver is used in this manner to decompose hydrogen pcroxid by catalysis it gradually suii'ers deterioration as a catalyte. The cause of this change may consist, first, in the fact that the ethereal solution of hydrogen peroxid to be used always contains traces of acid and that the quantity of this acid remaining in the picture will be increased by repeatedly dipping the picture into the ethereal solution of hydrogen peroxid. By this increase by and by the silver will he changed. On the other hand, two chemical actions may coexist, especially in the presence of acidviz., first, the principal reaction-that is to say, the catalytic decomposition of the hydrogen peroxid by the silveraud, secondly, an action of the hydrogen peroxid on the silver, by which action the changes of the silver mentioned above are produced. These coexisting reactions easily may cause inconveniences. Although this change in the silver may be delayed by exposing the silver negative or picture to ammonia-vapor, it is desirable to substitute for the silver a catalytc, which is more stable than silver under the conditions. As photographic negatives are generally produced in silver it is necessary to select a catalyte which can be produced by chemical change of the silver, so

that the negative obtained as usual may be converted into a more stable. form and then be used for printing by the process in question.

The present invention therefore consists in substiti'iting a stable catalyte for the silver for example, the higher oxygen compounds oi manganese. For instance, the silver negative or picture maybe treated with a solution of a manganic salt. Such solutions, however, are easily decomposed. Hitherto of the man-- ganic salts which are relatively stable in solution only the manganic phosphate was know 11. This phosphate may be used for substituting for silver the higher oxygen compounds of manganese. Particular-hf suitable, however. are such manganic-salt solutions as are to be obtained in the following manner:

When a solution of a manganous salt is mixed with a solution of potassium per manganate, there is formed a brown prezipitate, which is soluble in multi *aleut organic acids for example, tartaric acid. There is thus obtained a red-brown to greenish solution, which rapidly decomposes, but may be rendered stable by adding alkali until the reaction is alkaline. Stable solutions are also obtained it the aforesaid brown precipitate is tr atcd with salts of such organic acids. There arc'thus made dark alkaline solutions, which are stable for a iong time.

For securing stability of the solutions the proportions must in all cases be so chosen that the finished solution contains an excess of an alkali salt of the anion of the mauganic salt. These manganic-salt solutions are generally obtain ed in such a manner that the higher oxygen compounds of manganese or such manganese compounds as are capable of forming manganic compounds in the course of the further reaction are permitted to actupon multivalent organic acids or their salts. Vihcn no alkali is formed by the reaction, an alkali must be added, as it is essential to the stability of the solutions that they are alkaline.

The following are examples of how such stable solutions are prepared.

First. Manganic hydroxid is dissolved in an excess of tartaric acid andv the solution is mixed with sodium hydroxid until the reaction is alkaline.

Second. A solution of tartaric'acid is mixed with potassium permanganate in such proportion that there is an excess of tartaric acid, and sodium hydroxid is then added until the reac-- tion is alkaline.

twentv (20) cubic centimeters of ii solution of smlium liyd roxid ol three per cent. strength, and thirty (30) cubic centimeters of :1. solution oi potassium pernumgnmite of two per con t. strength.

The substitution of :1 picture in mnng'nnesc compound for that in silver may be cllccted, for example, by treating ti o silver picture with n solution of potassium ferrioynnid. tother with n nningnnic-snlt solution ol the 1nd liereinbciorc described and some acid--- er instance. hydrochloric ncid---until the :ihiclmess has completely disappeared. The negative or picture is then washed for :1 short time and brought into :2. solution of potassium 'hiiric cnid mid sodium hydroxid. The picture now assumes n. l)I'OW1'.. color. For exemplc suitable baths for operating in this manne are mad 1 as follows: First both, three cubic centiniietcrs of ii. men nic solution prepnred recording to cxsmpie four ubove, four- :md-zr-hnll cubic centimeters of hydrochloric acid of three-:uuhsi:c-tenths (3.6) per cent. strength, one hundred (100) cubic contimeters of n solution of potassium 'l erricyzinid seen of two per cent. strength; second bath. from ninety (90) to ninety-lire cubic centimeters o'l potn-ssium-lierricymiid solution, from l ve to ten (10) cubic centimeters of a solution of sodium hydroxid of four t) per cent. streng'tl llhc picture thus obtained is well suited for catalytic multiplication by means of hydrogen PGIOXiLl. if utter iong us it loses its ectivitgn this can easily be restored by treating the picture with ammoniavapor.

Vi hnt we claim is l. The process herein described of melting czitnlyzing' pictures of increased stnbility. which consists in suil'Jstituting by chemical notion for the unstable silver precipitate of the ordinary siivr pictures the more stable precipitate of a. higher oxygen compound of manganese.

2. The process herein described of making cutnlyzing' pictures of increased stability, which consists in treating on ordinnry silverprccipitete picture with n solution of potassium 'fcrricysi'lid together with a mnngenicsalt solution and on acid. then Washing the picture. and then subjectingthe snmeto the notion of n solution of potassium lerricynrid and sodium hydroxid.

in testimony that we claim the foregoing it our invention we have signed our names presence of two subscribing witnesses.

OSCAR (EROS. JAKOB i RlEDLi-iENDElI- l'l 'itncsses:

itUooLru FRIGKE, B. H. N Amine Jr. 

